Lifting-jack.



I'. L. GORMLEY.

LIFTING JACK.

APPLIOATION FILED IEB. 15, 1909.

Patented Sept. 7, 1909.

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EankL.GormZc y l l Y f III!! FRANK L. GORMLEY, OF BOSTON, MASSACHUSETTS.

LIFTING-JACK.

Specicaton of Letters Patent.

Application led February 15, 1909, Serial N o. 478,305.

fo all whom it may concern:

Be it known that I, F RANK L. GORMLEY, a citizen of the United States of America, and a resident of Boston, in the county of Suffolk and ,State of Massachusetts, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is specification.

rl'his invention relates to lifting jacks and particularly to that class of acks which are known as ratchet screw jacks, and has for its object the provision of a means whereby the movable member is prevented from being accidentally lowered under a heavy load.

The invention consists in interposing between the gear keyed to the lifting screw and the inner face of the movable member two plates separated by means of a plurality of anti-friction members with their outer faces respectively in contact with the gear upon the lifting screw and the inner face of the movable member, these two plates being connected together by some device such as a plurality of ratchet teeth upon one plate and a pawl upon the other plate whereby the plates are free to move about the axis of said lifting screw independently of one another in one direction while they will be obliged to move simultaneously in the opposite direction.

The invention consists in certain novel features of construction and arrangement of parts which will be readily understood by reference to the description of the drawings and to the claims hereinafter given.

Of the drawings: Figure 1 represents a horizontal section of a lifting jack embodying the features of this invention, the cutting plane being on line 1-1 on Fig. 2. Fig. 2 represents a vertical section of the same, the cutting plane being on line. 2-2 on Fig. 1. Fig. 3 represents an elevation of the friction devices interposed between the inner face of the movable member and the lifting screw gear. Fig. 4 represents an yinverted plan of the annular pawl carrying plate, and Fig. 5 represents a plan of one of the friction disks.

Similar characters designate like parts throughout the several figures of the drawn ings.

In the drawings,f10 represents a suitable base supporting a stationary standard 11 over the outerl periphery of which is fitted TEVGTSG a movable sleeve 12, to the upper end of which is threaded a head 13. 1n the upper end of the standard 11 is mounted a nut 14 to which is threaded a lifting screw 15 having splined to its upper' reduced end a gear 16 with which meshes a gear 17 formed upon or secured to a revoluble shaft 18, the outer end of which is provided with a suitable operating mechanism 19 of any well-known construction. Y

interposed between the upper face of the gear 16 and the inner face of the movable member 12 are two annular plates 2O and 21 between which are interposed a plurality of anti-friction members 22. Between the plate 2() and the innerpface of the movable niember 12 is a friction disk and between the annular plate 21 and the upper face of the gear 16 is a similar friction disk r1`he plate 21 is provided with a plurality of upwardly extending ratchet teeth 24 with which 'engage the pawls 25 pivotally mount ed on the annular disk 20 and forced downwardly into engagement with said teeth 24 by means of suitable springs 26.

lt is obvious that when the handle 19 is operated to move the gear 16 in the direction of the arrow indicated on Fig. 1 of the drawings the screw 15 will be so turned in the nut 14 as to cause the member 12 to be lifted relative to the standard 11 and during this rotation of the gear 16 the friction between the plate 21 and said gear 18 caused by the interposition of the friction disk 23 will be such as to cause the plate 21 to rotate with said gear, the teeth 24 thereon freely passing the pawl 25 without causing any rotation of the disk 20.

1t is obvious that if the load is light the gear 16 might revolve independently of the plate 21 without altering the principles of this invention. When an eXtra heavy load, however, is supported by the member 12 there is a tendency caused thereby owing to the coarsepitch of the screw 15 to turn in the nut 14. Owing to this extreme weight y direction will rotate with it the gear 16 and owing to the friction between this gear and the plate 21 cause this plate to simultaneously rotate therewith. 1n rotating in this manner the teeth 24 will engage with the pawls 25 pivotally mounted upon the plate 20 and owing to the abnormal friction Patented Sept. 7, 1909.

tendency of the screw 15 to turn in the between this plate 20 and the inner face of the movable member 12 the turningv of the screw I5 will be wholly'prevented" or limited to such an extent as to prevent any accident.

It is obvious that the accidental lowering of the movable member of the lifting jack is very dangerous and obviously objectionable and it is self-evident that by means of the construction hereinV shown and described that this objection is Wholly removed.

It is believed that from the foregoing-theV operation and many advantages of the invention will be fully understood.

Having thus described my invention, I claim:

1. In a lifting jack, the combination of a stationary member; a movable member thereon; a screw for said movable member; means for rotating said screw; a plate carried by said screw; a plate carried by said movable member; a plurality of anti-friction members interposed between said plates; and means for connecting and disconnecting said plates to insure the simultaneous'movement of said plates in one direction while permitting the independent movement of one of said plates in the opposite direction.

2. In a lifting jack; the combination of a stationary member; a movable member thereon a screw for said movable member; means for rotating said screw; a plate carried by said screw; a friction disk interposed between said plate and said screw; a plate carried by said movable member; a plurality of anti-friction members interposed between said plates; and means for connecting and disconnecting said plates to insure the simultaneous movement of said plates in one direction while permitting the independent movement of'one of said site direction.

3. In a lifting jack, the combination of a plates in the oppostationary member a movable member thereon; a screw for said movable member means for rotating said screw; a plate carried by said screw; a plate carried by said movable member; a friction disk interposed between said plate and said movable member; a plurality of anti-friction members interposed between said plates; and means for connecting` and disconnecting` said plates to insure the simultaneous movement of said plates in one direction while permitting the independent movement of one of said plates in the opposite direction.

4l. In a lifting jack, the combination of a stationary member; a movable member thereon; a screw for said movable member; means for rotating` said screw; a plate carried by said screw; a friction disk interposed between said plate and said screw; la plate carried by said movable member; a friction disk interposed between said plate and said and means for connecting and disconnecting said plates to insure'the simultaneous movement 'of said plates' in one direction while permitting the independent movement of one of said plates inthe opposite direction.

5. In a lifting jack, the combination of a stationary member; a movable member thereon; a screw for said movable member; means for rotating said screw; plate carried by said screw; a friction disk interposed between said plate and said screw; a plate carried by said movable member; a friction disk interposed between said` plate and said movable member; a plurality of antifriction members interposed Y between said plates; and a device secured to one of l said plates and engaging the other for connecting and disconnecting 'said plates to insure the simultaneous movement of said plates in one direction while permitting the in the opposite direction.

stationary member; a movable member thereon; a screw for said movable member; `means Vfor rotatingsaid screw; two plates interposed between said movable member and screw, one of said plates being provided with a plurality of teeth and the other having pivoted thereto a pawl engaging said` teeth; and a plurality of anti-friction members interposed between said plates.

7 In a lifting jack, the Vcombination of a stationary member; a movable member thereon; a screw for said movable member; means for rotating said screw; two. plates interposed between said movable member and screw, one of said plates being provided with a plurality of teeth and the other having pivoted thereto a pawl engaging said teeth; and a friction disk interposed between each plate and the member with which it coperates.

8. In a lifting jack; the combination of a stationary member; a movable member thereon; a screw for said movable member; means for rotating said screw; two plates interposed between said movable member and screw; and means for connecting and disconnecting said plates to permit one of them to rotate independently in one direction and insuring the rotation of both plates in unison in the opposite direction.

9. In a lifting jack, the combinationof a stationary member; a movable member thereon; a screw and nut for raisingy andrv lowering said movable member one of which is revoluble; and a divided device interposed between the revoluble member and said movwith adapted to permit said revoluble member to rotate freely in one direction but prevent the accidental rotation thereof in the movable member; a plurality of anti-friction members interposed between said plates; 1

opposite direction under a heavy load.

l0. In a lifting jack, the combination of independent movement of one of said. plates able member and in frictional contact there- 6. In a lifting jack, the combination of a a stationary member; a movable member opposite direction under a heavy load is pre- 10 thereon; a screw for Said movable member; vented.

a nut therefor; means for rotating said Signed by me at 4 Post Oii'ice Sq., Boston, Screw; and a divided friction device inter- Mass., this 28th day of January, 190,9.

posed between said screw rotating means FRANK L. GORMLEY.

and movable member and in rictional contact therewith adapted to permit said screw Witnesses:

rotating means to revolve freely in one di- WALTER E. LOMBARD, reotion While its accidental rotation in the EDNA C. CLEVELAND. 

